Help! Xlib error

[Ma, Qingyu (GE Healthcare)]

My application use openGL to draw some image on window, and modify led
state on keyboard through faking key event. The operations are executed
at 33ms interval.
If I add some system pressure, after long time execution, there is a
rare possibility to occur below two errors. 
 
#1
XIO: fatal IO error 0 (Success ) on X server "-"
       after 21 requests (9 known processed) with 0 event remaining.
 
#2
X Error of failed request:  BadLength (poly request too large or
internal Xlib length error)
  Major opcode of failed request:  148 (XTEST)
  Minor opcode of failed request:  2 (X_XTestFakeInput)
  Serial number of failed request:  16
  Current serial number in output stream:  20 X Error of failed request:
BadLength (poly request too large or internal Xlib length error)
  Major opcode of failed request:  148 (XTEST)
  Minor opcode of failed request:  2 (X_XTestFakeInput)
  Serial number of failed request:  15
  Current serial number in output stream:  20
 
 
I didn't find any clue in Xorg.0.log and message log.
The system pressure is, Mem: 40MB free and 500MB swap is used, CPU: 95%,
continuous disk writing, opengl demo(moving gear).
 
Could you please tell me what may cause these two errors?  It's urgent.
Thanks very much.
 
 
Best Regards,
Ma Qingyu
 
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